Ahead-thrown weapon for submarine warfare



Aug. 14, 1956 s. BURG AHEAD-THROWN WEAPON FOR SUBMARINE WARFARE FiledSept. 7, 1950 ATTORNEY}? AHEAD-THROWN,

This invention "relates to improvements in naval ordnance, and itsunderlying purpose is to provide a weapon to be used in submarinewarfare- Since the weapon is launched in air and is contrived not toexplode until it goes a prescribed distance underwater, the weapon issaid to embody the factor of discrimination which makes it remain inertwhile traversing a light medium and become activated only after enteringand traversing a denser medium. 'The principle of operation of theweaponis,

the building up'o'f internal hydrostatic pressure in-the depthcharge-containing cavity of an explosively inert rocket case orequivalent carrier when the water is struck,

thereby'to eject the depth charge. The primary development was that of apractice weapon to be used to simulate a depth charge attack from theunderwater explosion of which the accuracy of aim with respect to thetarget submarine vessel could be determined. This use, however, is not alimitation upon the invention because the I 7 identical principle wouldbe operative with full-scale components and in actual warfare.

The weapon comprises a carrier and a core. The carrier may consist ofthe appropriately modified rocket case shown herein or any similarlyconstituted case which is adapted to be projected through the air. Thecore consists of the depth charge. When this combination is assumed, inother words the depth charge is fitted inside of the rocket case, it iscalled an ahead-thrown Weapon and is adapted to be projected from arocket launcher, or it can merely be dropped from an aircraft.

From the foregoing brief outline it will be understood that one of theobjects of the invention is to provide an explosive weapon capable ofdiscriminating between air and water as the medium in which to explode.

Another object of the invention is to provide a weapon, intended hereinfor submarine warfare practice purposes but manifestly not so confined,wherein a depth charge is combined with an explosively inert rocket casefor trans? portation over an air trajectory to the surface of the water,separation occurring at water entry by the building up of internalhydrostatic pressure.

Another object of the invention is to provide for the building up of thehydrostatic pressure behind the depth charge, thereby to disconnect itfrom its superficial mooring and thereupon to eject the depth chargeclear of the rocket case.

Another object of the invention is to utilize the dissimilarity infrontal shapes of the depth charge and rocket case as an aid inproducing the separation of the depth charge from the rocket case.

Another object ofthe invention is to modify a known type of rocket caseby removing the fuze well and substituting a bottomed sleeve to form thewell, thereby to provide a cavity for the depth charge and so adapt the.rocket case as a carrier for the depth charge.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following United M States Patent detailed descriptionwhen considered connection with the accompanying drawings wherein: p

Fig. 1 is a combined sectional and elevational view of the ahead-thrownweapon;

Fig. 2 is a detail sectional view illustrating the detent and spacingmeans;

Fig. 3 is a cross section on the line 3-3 of Fig. 2, and

Fig. 4 is a cross section on the line 4-4 of Fig. 1.

In the drawings, the explosively inert rocket case 10 has combined withit an explosive depth charge 11. The rocket case has a sleeve well 12which is screwed in place in the thread course 13 in lieu of the fuzewell which otherwise could occupy this position. The well thus becomesan adapter sleeve, defining a cavity, open at the front and modifyingthe rocket case to support the depth charge along the longitudinalcenter of the case.

The inner end of the sleeve is bottomed at 14. The neck 15 into whichthe rocket motor .tube 16 is screwed is a seal-off. The compartment thusdefined in the case 10 is filled with water 17 or an equivalentexplosively inert material, to give the weapon the weight that it wouldhave were the filling 17 composed of an explosive substance. Three rods18 or their equivalent are welded to the inside of the sleeve well 120apart. They form a kept from sliding out of the sleeve well during airtransit of the weapon by a snap fastener 19.

The snap fastener as shown consists of a ring 21 from which the springfingers 23 which constitute the detent means extend. The spring fingersgrip the walls of a groove 22 in spacer means 24 to support the depthcharge clear of the bottom 14 so that the fins 26 will be saved fromdamage either upon inserting the depth charge or from the setback actionin projecting the weapon from a rocket launcher. The spacer means is asteel or equivalent piece, long enough to stand the fins clear of thebottom.

Spacing of the depth charge 11 from the internal walls of the sleevewell by the guide rods 18 and the means 24 produces an annular orifice.The front opening, now designated 28, provides Water access'to thisorifice. The spherical nose piece 29 of the depth charge protrudes atthis opening. The amount of protrusion beyond the ad j acent blunt face30 of the case 10 is from 1 /2" to 2%", depending on the length of thespacer means 24.

In practice the drag of the nose piece is much less per unit area thanthat of the orifice 27. As the result the pressure built up in theorifice and therefore on the interior of the sleeve well and behind thedepth charge is greater than the pressure on the nose piece. It is thispressure difference, due to the fact that rounded objects have less dragthan fiattobjects when pushed or pulled through water, which producesthe positive force that ejects the depth charge from the rocket case.Since the drag varies with the square of the velocity it follows thatthe separation force varies by the same factor. Therefore, the greaterthe air height drop or water entry ve locity, the greater the separationforce upon the depth charge.

The operation is reviewed briefly. The rocket case 10 is loaded byinserting the depth charge 11 into the sleeve well cavity tail first.The spacer means 24 supports the fins 26 clear of the bottom 14. Ampleroom is thus as-' trajectory. It is here that the factor ofdiscrimination enters. The depth charge is disconnected from its mooringand ejected, as has been pointed out. Another factor assists in thisseparation. The mere impact of the blunt is put on the automatichydrostatic thrust build-up behind the depth charge.

The latter'will explode according to its setting. The

sound of the explosion can be detected underwater over a distance ofseveral miles. The sound detection is made by the target submarinevessel, and it is by the latter that the accuracy of the simulatedattack is evaluated. 7

Obviously modifications and variations of the present invention arepossible in thelight of the above teach-' ings. It is therefore to beunderstood that within the scope of the appended claim the invention maybe practiced otherwise than'as specifically described.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalties thereon or therefor.

What is claimed is:

An item of ordnance comprising the combination of an elongated finnedtype carrier missile having a cavity open only at the front end thereofand a bottom internally of the carrier, said carrier being configured topass head-on through a body of Water, a detachably mounted core missilenormally disposed'in the cavity of said carrier missile having a roundednose portion exposed only at the open end of the cavity and a finnedtail section disposed adjacent the bottom of said cavity, means forreleasably latching the core missile in said cavity, said last namedmeans having spring portions for frictionally engaging a mating portionof said core missile when it is bottomed, guide rod means for spacingthe core from the inside wall of the cavity and coact-ing with the finsof said core missile to provide for Water access and the building up ofhydrostatic pressure between the cavity bottom and I the tail section ofthecore missile in excess of the pressure on 'therounded nose portion,thereby to cause separation of the core from the carrier only upon entryof the said item into abody of water following launching thereof. 1 ,6

References Cited in the file of this patent UNITED STATES PATENTS 36,686Callender 061. 14, 1862 1,184,699 Kenney May 23, 1916 1,275,686 HillAug. 13, 1918 1,303,499 Romain May 13, 1919 1,409,409 Rist Mar. 14, 1922I 1 FOREIGN PATENTS 75,404 Austria Feb. 10, 1919 406,574 Great BritainMar. 1, 1934 539,699 Great Britain Sept. 22, 1941

